1. Field
This specification relates to a wireless power transfer method, apparatus and system in a wireless power transfer field.
2. Background
In recent years, the method of contactlessly supplying electrical energy to wireless power receivers in a wireless manner has been used instead of the traditional method of supplying electrical energy in a wired manner. The wireless power receiver receiving energy in a wireless manner may be directly driven by the received wireless power, or a battery may be charged by using the received wireless power, then allowing the wireless power receiver to be driven by the charged power.
The Wireless Power Consortium (WPC) which manages technologies for a magnetic inductive wireless power transfer has published a standard document “System description Wireless Power Transfer, Volume 1, Low Power, Part 1: Interface Definition, Version 1.00 Release Candidate 1 (RC1)” for interoperability in the wireless power transfer on Apr. 22, 2010. The standard document of the WPC has described a method of transferring power from one wireless power transmitter to one wireless power receiver by a magnetic induction.
The version 1.00 is involved with low power of 5 W power transmission and reception. A standard for power transfer over 5 W has not currently been defined in the wireless power transfers regulated in the WPC but a specification for medium power transmission and reception over 5 W is expected to be carried out.